Cholecystokinin receptors in the brain: characterization and distribution

Science ◽  
1980 ◽  
Vol 208 (4448) ◽  
pp. 1155-1156 ◽  
Author(s):  
A Saito ◽  
H Sankaran ◽  
ID Goldfine ◽  
JA Williams
Keyword(s):  
Biological Activity ◽  
Rat Brain ◽  
Dissociation Constant ◽  
Binding Sites ◽  
Brain Regions ◽  
High Affinity ◽  
Cholecystokinin Receptors ◽  
Iodine 125 ◽  
The Brain

Specific cholecystokinin binding sites in particulate fractions of rat brain were measured with iodine 125-labeled Bolton-Hunter cholecystokinin, a cholecystokinin analog that has full biological activity. Binding was detected in brain regions known to contain immunoreactive cholecystokinin. Binding was saturable, reversible, of high affinity (dissociation constant, 1.7 x 10(-9) M), and was inhibited by cholecystokinin analogs but not by unrelated hormones.

High-affinity choline uptake in regions of rat brain and the effect of antidepressants

1979 ◽  
Vol 57 (6) ◽  
pp. 595-599 ◽  
Author(s):  
P. D. Hrdina ◽  
K. Elson
Keyword(s):  
Rat Brain ◽  
Tricyclic Antidepressants ◽  
Brain Regions ◽  
Choline Uptake ◽  
Dependent Manner ◽  
Choline Transport ◽  
High Affinity ◽  
Michaelis Constants ◽  
Dose Dependent ◽  
The Brain

The effect of tricyclic antidepressants, chlorpromazine, and some monoamine oxidase inhibitors on the accumulation of [14C]choline by crude synaptosomal (P2) fraction from different regions of rat brain (cortex, striatum, and hippocampus) was investigated. Analysis of choline uptake kinetics resulted in high- and low-affinity components with different Michaelis constants. All tricyclic antidepressants tested inhibited in a dose-dependent manner the high-affinity choline uptake in the three regions, amitriptyline being the most potent. The IC50 values correlated significantly with the relative potencies of imipramine congeners in binding to muscarinic receptors in the brain. Neither tranylcypromine nor pargyline in concentrations up to 0.1 mM had any effect on choline transport. Concentrations of tricyclic antidepressants effective in inhibiting the uptake of choline failed to influence significantly the activity of choline acetyltransferase in brain regions examined. The results suggest that the effect of imipramine congeners on high-affinity choline uptake may be reflected in the anticholinergic properties of these compounds.

scholarly journals [3H]-ouabain binding sites in rat brain: distribution and properties assessed by quantitative autoradiography.

1992 ◽  
Vol 40 (6) ◽  
pp. 771-779 ◽  
Author(s):  
A A Maki ◽  
D G Baskin ◽  
W L Stahl
Keyword(s):  
Nervous System ◽  
Rat Brain ◽  
Cardiac Glycoside ◽  
Binding Sites ◽  
Quantitative Autoradiography ◽  
Affinity Binding ◽  
Ouabain Binding ◽  
High Affinity Binding ◽  
High Affinity ◽  
Kd Values

The anatomic distribution of high- and low-affinity cardiac glycoside binding sites in the nervous system is largely unknown. In the present study the regional distribution and properties of these sites were determined in rat brain by quantitative autoradiography (QAR). Two populations of cardiac glycoside binding sites were demonstrated with [3H]-ouabain, a specific inhibitor of Na,K-ATPases: (a) high-affinity binding sites with Kd values of 22-69 nM, which were blocked by erythrosin B, and (b) low-affinity binding sites with Kd values of 727-1482 nM. Sites with very low affinity for ouabain were not found by QAR. High- and low-affinity [3H]-ouabain binding sites were both found in all brain regions studied, including somatosensory cortex, thalamic and hypothalamic areas, medial forebrain bundle, amygdaloid nucleus, and caudate-putamen, although the distributions of high- and low-affinity sites were not congruent. Low-affinity [3H]-ouabain binding sites (Bmax = 222-358 fmol/mm2) were approximately twofold greater in number than high-affinity binding sites (Bmax = 76-138 fmol/mm2) in these regions of brain. Binding of [3H]-ouabain to both high- and low-affinity sites was blocked by Na+; however, low-affinity binding sites were less sensitive to inhibition by K+ (IC50 = 6.4 mM) than the high-affinity [3H]-ouabain binding sites (IC50 = 1.4 mM). The QAR method, utilizing [3H]-ouabain under standard conditions, is a valid method for studying modulation of Na,K-ATPase molecules in well-defined anatomic regions of the nervous system.

Autoradiographic distribution in rat tissues of binding sites for endothelin: a neuropeptide?

1989 ◽  
Vol 256 (4) ◽  
pp. R858-R866 ◽  
Author(s):  
C. Koseki ◽  
M. Imai ◽  
Y. Hirata ◽  
M. Yanagisawa ◽  
T. Masaki
Keyword(s):  
Binding Sites ◽  
Rat Tissues ◽  
Binding Assays ◽  
Heart Ventricle ◽  
High Affinity ◽  
Long Acting ◽  
Porcine Endothelial Cells ◽  
Vasoconstrictor Peptide ◽  
The Brain

Endothelin (ET) is a potent and long-acting vasoconstrictor peptide consisting of 21 amino acids and recently isolated from a medium of cultured porcine endothelial cells. To determine the possible sites of ET action, we have conducted autoradiography and receptor binding assays with 125I-labeled ET in rat tissues. The displaceable binding sites of the ligand were widely distributed, not only in the arteries and heart but also in various other organs, e.g., brain, kidney, lung, adrenal gland, and intestine. The systemically injected ET did not cross the blood-brain barrier, whereas the ligand, applied in vitro, was mainly located in the hypothalamic and thalamic areas, lateral ventricular region, subfornical organ, globus pallidus, and caudate putamen. Both membrane preparations from the brain stem including diencephalon and from the heart ventricle had similar, specific, and high-affinity binding sites for 125I-ET. We suggest that ET is involved in the regulation of a large variety of organ functions and may also act as a neuropeptide.

Intrinsic, apparent, and effective affinities of co- and countertransport systems

1986 ◽  
Vol 250 (4) ◽  
pp. C523-C533 ◽  
Author(s):  
W. D. Stein
Keyword(s):  
Dissociation Constant ◽  
Chemical Reaction ◽  
Binding Sites ◽  
Kinetic Schemes ◽  
High Affinity ◽  
Dependent Atpase ◽  
Conformation Changes ◽  
Rapid Equilibrium

Solutions to kinetic schemes for the simple carrier, the countertransporter (antiport, exchanger), and the rapid equilibrium cases of the cotransporter (symport) and co-chemiporter (cation-dependent ATPase) are listed. A distinction is made between the intrinsic, apparent, and effective affinities of the transporters for their substrates. Effective pumping requires that the active transporter binds the pumped substrate, at high affinity, realized at the “whence side” (from which pumping takes place) and, at low affinity, at the “whither side” (to which pumping takes place). It is demonstrated how effective pumping might be achieved by appropriate design of the transporter or chemiporter in terms of the energies of the intrinsic binding sites, the energies of the conformation changes that the pump protein undergoes, the dissociation constant of the chemical reaction that drives the co-chemiport, and the order of binding of the cosubstrates, appropriate at different prevailing levels of the driving substrate.

Levels of specifically bound [3H]ketanserin compared with levels of serotonin (5HT) in the brain regions of juvenile and sexually recrudescing female rainbow trout, Oncorhynchus mykiss

2000 ◽  
Vol 78 (3) ◽  
pp. 228-236 ◽  
Author(s):  
Smriti M Agrawal ◽  
Robert J Omeljaniuk
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Electrochemical Detection ◽  
Binding Sites ◽  
High Performance ◽  
Preoptic Area ◽  
Brain Regions ◽  
Olfactory Lobe ◽  
Rainbow Trout Oncorhynchus Mykiss ◽  
The Brain

This study compared the distribution of specifically bound [3H]ketanserin (Bsp) with serotonin (5HT) in brain regions of juvenile and sexually recrudescing female trout. Amounts of Bsp varied widely among brain regions and consistently differed between juvenile and sexually recrudescing females. Levels of Bsp were significantly greater in the hypothalamus than the olfactory lobe, which were at least threefold greater than in all other tissues examined (Kruskal-Wallis test, p < 0.05). Bsp densities in the hypothalamus, preoptic area, and optic lobe were significantly greater in juveniles compared with corresponding tissues from sexually recrudescing females (Mann-Whitney U test, p < 0.05); in contrast, Bsp in olfactory lobe and spinal cord did not differ significantly between the two classes of fish. 5HT concentration was determined by high performance liquid chromatography - electrochemical detection (HPLC-EC) analysis. Biogenic amine standards eluted in a stereotypic pattern, with peaks consistently separable in time. 5HT concentration was significantly greater in hypothalamus than in olfactory lobe and undetectable in the pituitary (Kruskal-Wallis test, p < 0.05). Trends in distribution of Bsp and 5HT were comparable in the hypothalamus and preoptic area in juvenile and sexually recrudescing females. In general, density of specific [3H]ketanserin binding sites was directly related to 5HT content of brain regions in juvenile and sexually recrudescing females. 5HT concentrations (pmol/g tissue) were approximately 900-fold greater than Bsp (fmol/g tissue) in all brain regions, and approximately 300-fold greater than Bsp in the olfactory lobe. These results suggest important regulatory role(s) for 5HT in the trout preoptic-hypothalamo-hypophysial axis, which may differ from 5HT role(s) in trout olfactory lobe.Key words: high performance liquid chromatography - electrochemical detection, [3H]ketanserin, sexually recrudescing female trout.

scholarly journals Effect of Phospholipase A2 on Temperature-Induced High-Affinity (3H)Tryptamine Binding Sites in Rat Brain.

1991 ◽  
Vol 56 (4) ◽  
pp. 413-419 ◽  
Author(s):  
Michiko Saito ◽  
Shigefumi Serikyaku ◽  
Ryoichi Ishitani
Keyword(s):  
Phospholipase A2 ◽  
Rat Brain ◽  
Binding Sites ◽  
High Affinity
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